Upload super sangat sederhana

<?php
/*
SANGAT BUTUH FOLDER TMP

*/
if($_FILES) {
    $t=mktime();
    foreach($_FILES[my] as $nm=>$v) $$nm=$v;

    copy($_FILES[my][tmp_name], 'tmp/'.$t.".tmp");
    $f=file_get_contents('t.txt'); $f.="\n$t\t$name\t$type\t$size";
    $handle = fopen('t.txt', "w");
    fwrite($handle, $f);
    fclose($handle);

}

$f=file_get_contents('t.txt');
$a=explode("\n",$f);
if($_GET[a]=='down')
{
    foreach($a as $v)
    {
        $a2=explode("\t",$v);
        if($a2[0]==$_GET[id])
        {
            header('Content-type:'.$a2[2]);
            header('Content-Disposition: attachment; filename="'.$a2[1].'"');
            $f2=file_get_contents('tmp/'.$a2[0].'.tmp');
            die($f2);

        }

    }

}

$s=count($a)."<ol>";
foreach($a as $v)
{
    $a2=explode("\t",$v);
    $s.="<li><a href='?a=down&id=$a2[0]'>$a2[1]</a> ($a2[2])";
}
$s.="</ol>";

?>
<form enctype='multipart/form-data' method='post'>
<input type=file name='my' />
<input type=submit> </form> <? echo $s;
//phpinfo();